Percentage Calculator
Three percentage problems cover almost everything people ask: what is X% of Y, what percent is X of Y, and how much did something change in percent. This page does all three — type any two numbers and the answer appears instantly, with the formula shown so you can check the working.
Percentages trip people up because the same words mean different operations. '20% of 150' is a multiplication; '15 is what percent of 60' is a division; 'price went from 80 to 100' is a change calculation. Instead of remembering which formula fits, just pick the tab that matches your question.
How to use
- Pick the tab that matches your question: 'X% of Y', 'X is what % of Y', or '% change from X to Y'.
- Type your two numbers — the answer appears instantly as you type, no button needed.
- Read the formula line under the result to see exactly how the answer was calculated.
Frequently asked questions
How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. For example, 20% of 150 = 150 × 20 ÷ 100 = 30. The first tab of this calculator does it instantly.
How do I work out percentage increase?
Subtract the old value from the new value, divide by the old value, and multiply by 100. Going from 80 to 100 is (100 − 80) ÷ 80 × 100 = 25% increase. Use the third tab.
What is the formula for percentage change?
Percentage change = (new − old) ÷ |old| × 100. A positive result is an increase, a negative result is a decrease. The calculator shows the sign automatically.
How do I calculate a discount percent?
Divide the amount saved by the original price and multiply by 100. For example, saving $12 on a $60 item is 12 ÷ 60 × 100 = 20% off.